RELAXATION OF REGULARITY FOR THE WESTERVELT EQUATION BY NONLINEAR DAMPING WITH APPLICATIONS IN ACOUSTIC-ACOUSTIC AND ELASTIC-ACOUSTIC COUPLING.

In this paper we show local (and partially global) in time existence for the Westervelt equation with several versions of nonlinear damping. This enables us to prove well-posedness with spatially varying L_∞-coefficients, which includes the situation of interface coupling between linear and nonlinear acoustics as well as between linear elasticity and nonlinear acoustics, as relevant, e.g., in high intensity focused ultrasound (HIFU) applications. [ABSTRACT FROM AUTHOR]